Linux: use GTK sink for Wayland Bambu liveview (#13432)

* Use GTK sink for Wayland liveview

Keep native Wayland sessions on the GTK backend and use a GTK widget based GStreamer sink for Bambu liveview instead of the Wayland video overlay path, which can render black on NVIDIA/Hyprland.

Keep the existing wxMediaCtrl path for X11 and continue preferring software H.264 decoding while demoting GL and hardware decoder paths that caused liveview crashes.

* Narrow Linux liveview fix to native Wayland

* Tighten native Wayland liveview setup

* Tighten Wayland liveview teardown and rank setup

* Package GStreamer gtksink for Wayland liveview

---------

Co-authored-by: SoftFever <softfeverever@gmail.com>

src/slic3r/GUI/wxMediaCtrl2.h

@@ -13,6 +13,10 @@
 
 wxDECLARE_EVENT(EVT_MEDIA_CTRL_STAT, wxCommandEvent);
 
+#if defined(__LINUX__) && defined(__WXGTK__)
+typedef struct _GstElement GstElement;
+#endif
+
 #ifdef __WXMAC__
 
 class wxMediaCtrl2 : public wxWindow
@@ -59,6 +63,7 @@ class wxMediaCtrl2 : public wxMediaCtrl
 {
 public:
     wxMediaCtrl2(wxWindow *parent);
+    ~wxMediaCtrl2();
 
     void Load(wxURI url);
 
@@ -68,6 +73,8 @@ public:
 
     void SetIdleImage(wxString const & image);
 
+    wxMediaState GetState();
+
     int GetLastError() const;
 
     wxSize GetVideoSize() const;
@@ -84,6 +91,21 @@ protected:
 #endif
 
 private:
+#if defined(__LINUX__) && defined(__WXGTK__)
+    bool CreateGtkSinkPlayer();
+    void DestroyGtkSinkPlayer();
+    void PostGtkSinkStateEvent(int id = 0);
+
+    bool m_native_wayland = false;
+    bool m_use_gtk_sink = false;
+    wxString m_gtk_sink_error;
+    bool m_gtk_sink_error_notified = false;
+    GstElement *m_gtk_playbin = nullptr;
+    GstElement *m_gtk_sink = nullptr;
+    unsigned int m_gtk_bus_watch_id = 0;
+    wxWindow *m_gtk_video_window = nullptr;
+    wxMediaState m_gtk_state = wxMEDIASTATE_STOPPED;
+#endif
     wxString m_idle_image;
     int      m_error = 0;
     bool     m_loaded = false;